Boat model making is an art that is very old. In the early days of making large scale sailing vessels, an initial step involved the manufacture of a scaled down model that would resemble the final vessel as closely as possible. Such model would include frames or ribs to which planks could be fastened with a flush (fair) fit. These frames would be affixed to a keel rib and when so attached would define both the external hull contour and the inboard contour. Ship hull contours are complex and dictate that the inboard as well as outboard faces of most of the frames are different to obtain a flush fit of the outside planks and stringers employed inside to reinforce the hull. The ship hull contours commonly require that the internal and external surfaces of any one frame have different bevels at different locations along the length of the frame. The making of an accurate model for a ship thus involved a substantial effort and time.
Boat model making is also a hobby with many books written on the subject. See, for example, "Plank-on-Frame Models and Scale Masting and Rigging" Volume I, by H. A. Underhill published by Brown, Son and Ferguson Ltd., Glasgow 1971. In this book a section is devoted to the making of a true plank-on-frame model (see page 38 and FIG. 5) where the frames have the desired bevels so as to obtain a fair and flush fitting of planks when these are applied.
Techniques have been proposed to make so-called plank-on-frame boat models, though these in practice do not use truly authentic beveled frames. For example, the U.S. Patent to Wilcox, No. 1,259,572 describes a boat hull wherein the frames, or ribs as they are also called, are formed of a plate of wood with the edges of the plate beveled in accordance with the angle of the boat model skin. Beveling is effected with a lathe or turning machine so that a plurality of ribs can be simultaneously beveled. This technique does not produce a true plank-on-frame design in that it does not provide an inboard bevel on the frames and does not obtain a bevel which varies over the height of the frame as is frequently required.
Similar shortcomings are found in other boat model art such as U.S. Pat. Nos. to Dean, 833,511; Shaver, 1,639,707; Gordon, 1,994,274; Chlopicki, 2,243,372 and Surving, 3,793,768; as well as British Pat. No. 607,241 to Lyons.
When boat models using a true plank-on-frame construction are to be made, the complexity in the manufacture of the frames or ribs with their compound surfaces tends to render such models to be excessively complex and expensive to make.